Transport of Scylla serrata megalopae at various densities and durations

The optimal conditions for transport of Scylla serrata megalopae were deter mined. Loading densities of 50, 100 and 150 ind 1(-1) of hatchery-reared me galopae were studied over a 6-h simulated transport, including shaking. Sur vival immediately after transport was significantly higher at 50 ind 1(-1) (99.3 +/- 1.6%) (mean +/- x%) than at 100 (93.0 +/- 5.0) and 150 ind 1(-1) (94.0 +/- 3.8%). The same trend was noted 15 h after transport. Another exp eriment compared survival of megalopae packed at 50 and 100 ind 1(-1) with simulated transport of various durations (3, 6, and 9 h) at mobile and stat ionary conditions. Regardless of the duration and condition of transport, s urvival was again significantly higher at 50 ind 1(-1) (86.7 +/- 2.4%) comp ared to 100 ind 1(-1) (79.7 +/- 2.1%). Megalopae that were shaken or remain ed unshaken for 3 or 6 h had similar survival through transport as those sh aken for 9 h. Megalopae that remained unshaken for 9 h gave the lowest surv ival among treatment groups (38.7 +/- 0.2%). Due to cannibalistic behavior, stationary transport conditions may have pro vided the megalopae with a chance to grasp each other. In a third experimen t, a batch of megalopae was packed at water temperature levels of 20, 24, a nd 28 degrees C (ambient) at 50 and 100 ind 1(-1) for 6 h simulated transpo rt, including shaking. Density and temperature separately influenced surviv al. Survival was lower at 28 degrees C than 24 degrees C. Although megalopa e were less active at 20 degrees C, survival was similar to that at 24 degr ees C and 28 degrees C. These results provide useful information for megalo pae transport from hatchery to ponds. (C) 2000 Elsevier Science B.V. All ri ghts reserved.